Orthodontists and dental researchers are constantly searching for new and improved ways to correct the problem of upper jaw constriction with collapsed dental arch causing lingual cross bites or overly wide upper jaw and dental arch causing buccal posterior cross bites.
Posterior cross bites are the most common dental malocclusion in young or adult patients due to various etiologies. The condition due to insufficient maxillary arch width in various dimensions can cause further skeletal growth problems if left untreated. The overgrown width of the upper jaw also by causing buccal cross bite can cause significant damage to the dentition and growth of the temporomandibular joints. Expansion of the maxilla relies on rapid palatal expander devices that deliver forces to break the mid-palatal and circum-maxillary sutures to facilitate transverse and sagital dento-facial correction.
Current orthodontic devices for spreading the jaws, dental arches, or contracting the dental arches have not been entirely satisfactory because such devices are capable of performing only one of parallel expansion, parallel contraction, fan shape expansion, or fan shape contraction of the jaws and dental arches. Current expansion appliances such as HYRAX (tooth borne) and HAAS expander (tooth and tissue borne) designs are limited to transverse bilateral and parallel expansion in the posterior region of the maxilla. As a result, they lack the differential nonparallel expansion or contraction capability unless sequentially used in combination with fan shape design expanders. As a result, in most cases with V-shape maxillary arch forms (wider in the back than front), during the expansion of the premolar or canine sections to proper width, the molar areas can get over-expanded, causing buccal cross bite in the molar areas. This impact can be opposite in significant U-shape maxillary constriction, causing the premolar and canine teeth end up in over-extend or buccal cross bite as the molar areas are expanded to the ideal width.